As a clinical subtype of CRC, CAC has numerous similar molecular mechanisms to CRC, including: 1) both of them originate from abnormally developed precursor lesions; 2) the mutation frequencies of key genes including adenomatous polyposis coli (APC), tumor suppressor protein p53 (p53), small mothers against decapentaplegic 4 (SMAD4), and kirsten rat sarcoma virus (KRAS) causing carcinogenesis between the two are equivalent (Clevers, 2004). Here, SMAD4 is linked to colorectal carcinoma.